Hi,
First of all, it's my first post here so... hey everyone!
I am having trouble with Nero AAC Encoder when encoding to .m4a.
When using the command line application to convert to a regular wav file to a m4a with the following parameters:
-b 48 -w (48kbps wrapped in MPEG4)
Most of the resulting files will have 48kbps but for some reason some files will end up being 49kbps.
It is very important that the file have exactly 48kbps since I upload them to a web site that does not allow anything but 48kbps.
Anyone has an idea why & how to fix this ? A better command line encoder for m4a ?
Let me know!
Thank you
Stimpy
Full Version: Nero AAC Encoder Bitrate Issue for m4a?
Are you sure you are using the Nero encoder? Those options (-b and -w) are not supported.
But in general, yes this can happen, because of the bit reservoir for example. Even the CBR mode for AAC is usually not really CBR, but slightly varying.
But in general, yes this can happen, because of the bit reservoir for example. Even the CBR mode for AAC is usually not really CBR, but slightly varying.
hey thanks,
i'm sorry, i confused my settings. These are the ones I use:
-cbr 48000
Plain and simple. You say this is normal. But when I use Easy CD Extractor to create a m4a from a file that ended at 49kbps, it encodes it perfectly at 48kbps.
I know the application is using their own compiled version the FAAC lib. I tried the FAAC Command line Encoder aswell and it ended up being worse since there is no built in options for constant bit rates... I beleive. I just want my outputs to be dead on at 48kbps.
Thank you.
i'm sorry, i confused my settings. These are the ones I use:
-cbr 48000
Plain and simple. You say this is normal. But when I use Easy CD Extractor to create a m4a from a file that ended at 49kbps, it encodes it perfectly at 48kbps.
I know the application is using their own compiled version the FAAC lib. I tried the FAAC Command line Encoder aswell and it ended up being worse since there is no built in options for constant bit rates... I beleive. I just want my outputs to be dead on at 48kbps.
Thank you.
QUOTE(Stimpy @ Aug 14 2008, 23:21) 
Plain and simple. You say this is normal. But when I use Easy CD Extractor to create a m4a from a file that ended at 49kbps, it encodes it perfectly at 48kbps.
do you realize that 1kbps are 125bytes each second?
As an example, your second post sizes (with ASCII encoding) 531bytes.
Said that, AAC is not strict when talking about CBR. In other words, its CBR encoding does not enforce that over the period of one second, it has to have exactly X bytes. There's an allowable window, so that MP3's bit reservoir is not needed (or much less needed) with AAC.
Said that, i've read in other posts about Nero that this deviance has been worked some, and it should happen less often.
[Edit: obviously, what FAAC does is be more strict than what the standard requires, and that's why it keeps at 48kbps]
nice. thanks for explaining.
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